|Date|Constituency|Gain|Loss|Note|
|---|---|---|---|---|
|30 May 1963|Dublin North–East|Fine Gael|Fine Gael|Paddy Belton (FG) holds the seat vacated by the death of his brother Jack Belton (FG)|
|27 October 1963|Dublin South–East|Labour Party|National Progressive Democrats|Noël Browne (NPD) disbands the National Progressive Democrats and joins the Labour Party|
|27 October 1963|Roscommon|Labour Party|National Progressive Democrats|Jack McQuillan (NPD) disbands the National Progressive Democrats and joins the Labour Party|
|27 October 1963|Dublin County|Labour Party|Independent|Seán Dunne (Ind) joins the Labour Party|
|19 February 1964|Cork Borough|Fianna Fáil|Fianna Fáil|Sheila Galvin (FF) wins the seat vacated by the death of her husband John Galvin (FF)|
|19 February 1964|Kildare|Fianna Fáil|Labour Party|Terence Boylan (FF) wins the seat vacated by the death of William Norton (Lab)|
|8 July 1964|Roscommon|Fine Gael|Fine Gael|Joan Burke (FG) holds the seat vacated by the death of her husband James Burke (FG)|
|3 December 1964|Galway East|Fine Gael|Clann na Talmhan|John Donnellan (FG) wins the seat vacated by the death of his father Michael Donnellan (CnaT)|
|10 March 1965|Cork Mid|Labour Party|Labour Party|Eileen Desmond (Lab) holds the seat vacated by the death of her husband Dan Desmond (Lab)|

Question: what's the total number of dates listed for 1964?
Answer: 4